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- // SPDX-License-Identifier: GPL-2.0+
- /*
- * EFI boot manager
- *
- * Copyright (c) 2017 Rob Clark
- */
- #define LOG_CATEGORY LOGC_EFI
- #include <common.h>
- #include <charset.h>
- #include <log.h>
- #include <malloc.h>
- #include <efi_loader.h>
- #include <efi_variable.h>
- #include <asm/unaligned.h>
- static const struct efi_boot_services *bs;
- static const struct efi_runtime_services *rs;
- /*
- * bootmgr implements the logic of trying to find a payload to boot
- * based on the BootOrder + BootXXXX variables, and then loading it.
- *
- * TODO detecting a special key held (f9?) and displaying a boot menu
- * like you would get on a PC would be clever.
- *
- * TODO if we had a way to write and persist variables after the OS
- * has started, we'd also want to check OsIndications to see if we
- * should do normal or recovery boot.
- */
- /**
- * efi_deserialize_load_option() - parse serialized data
- *
- * Parse serialized data describing a load option and transform it to the
- * efi_load_option structure.
- *
- * @lo: pointer to target
- * @data: serialized data
- * @size: size of the load option, on return size of the optional data
- * Return: status code
- */
- efi_status_t efi_deserialize_load_option(struct efi_load_option *lo, u8 *data,
- efi_uintn_t *size)
- {
- efi_uintn_t len;
- len = sizeof(u32);
- if (*size < len + 2 * sizeof(u16))
- return EFI_INVALID_PARAMETER;
- lo->attributes = get_unaligned_le32(data);
- data += len;
- *size -= len;
- len = sizeof(u16);
- lo->file_path_length = get_unaligned_le16(data);
- data += len;
- *size -= len;
- lo->label = (u16 *)data;
- len = u16_strnlen(lo->label, *size / sizeof(u16) - 1);
- if (lo->label[len])
- return EFI_INVALID_PARAMETER;
- len = (len + 1) * sizeof(u16);
- if (*size < len)
- return EFI_INVALID_PARAMETER;
- data += len;
- *size -= len;
- len = lo->file_path_length;
- if (*size < len)
- return EFI_INVALID_PARAMETER;
- lo->file_path = (struct efi_device_path *)data;
- /*
- * TODO: validate device path. There should be an end node within
- * the indicated file_path_length.
- */
- data += len;
- *size -= len;
- lo->optional_data = data;
- return EFI_SUCCESS;
- }
- /**
- * efi_serialize_load_option() - serialize load option
- *
- * Serialize efi_load_option structure into byte stream for BootXXXX.
- *
- * @data: buffer for serialized data
- * @lo: load option
- * Return: size of allocated buffer
- */
- unsigned long efi_serialize_load_option(struct efi_load_option *lo, u8 **data)
- {
- unsigned long label_len;
- unsigned long size;
- u8 *p;
- label_len = (u16_strlen(lo->label) + 1) * sizeof(u16);
- /* total size */
- size = sizeof(lo->attributes);
- size += sizeof(lo->file_path_length);
- size += label_len;
- size += lo->file_path_length;
- if (lo->optional_data)
- size += (utf8_utf16_strlen((const char *)lo->optional_data)
- + 1) * sizeof(u16);
- p = malloc(size);
- if (!p)
- return 0;
- /* copy data */
- *data = p;
- memcpy(p, &lo->attributes, sizeof(lo->attributes));
- p += sizeof(lo->attributes);
- memcpy(p, &lo->file_path_length, sizeof(lo->file_path_length));
- p += sizeof(lo->file_path_length);
- memcpy(p, lo->label, label_len);
- p += label_len;
- memcpy(p, lo->file_path, lo->file_path_length);
- p += lo->file_path_length;
- if (lo->optional_data) {
- utf8_utf16_strcpy((u16 **)&p, (const char *)lo->optional_data);
- p += sizeof(u16); /* size of trailing \0 */
- }
- return size;
- }
- /**
- * get_var() - get UEFI variable
- *
- * It is the caller's duty to free the returned buffer.
- *
- * @name: name of variable
- * @vendor: vendor GUID of variable
- * @size: size of allocated buffer
- * Return: buffer with variable data or NULL
- */
- static void *get_var(u16 *name, const efi_guid_t *vendor,
- efi_uintn_t *size)
- {
- efi_status_t ret;
- void *buf = NULL;
- *size = 0;
- ret = efi_get_variable_int(name, vendor, NULL, size, buf, NULL);
- if (ret == EFI_BUFFER_TOO_SMALL) {
- buf = malloc(*size);
- ret = efi_get_variable_int(name, vendor, NULL, size, buf, NULL);
- }
- if (ret != EFI_SUCCESS) {
- free(buf);
- *size = 0;
- return NULL;
- }
- return buf;
- }
- /**
- * try_load_entry() - try to load image for boot option
- *
- * Attempt to load load-option number 'n', returning device_path and file_path
- * if successful. This checks that the EFI_LOAD_OPTION is active (enabled)
- * and that the specified file to boot exists.
- *
- * @n: number of the boot option, e.g. 0x0a13 for Boot0A13
- * @handle: on return handle for the newly installed image
- * Return: status code
- */
- static efi_status_t try_load_entry(u16 n, efi_handle_t *handle)
- {
- struct efi_load_option lo;
- u16 varname[] = L"Boot0000";
- u16 hexmap[] = L"0123456789ABCDEF";
- void *load_option;
- efi_uintn_t size;
- efi_status_t ret;
- varname[4] = hexmap[(n & 0xf000) >> 12];
- varname[5] = hexmap[(n & 0x0f00) >> 8];
- varname[6] = hexmap[(n & 0x00f0) >> 4];
- varname[7] = hexmap[(n & 0x000f) >> 0];
- load_option = get_var(varname, &efi_global_variable_guid, &size);
- if (!load_option)
- return EFI_LOAD_ERROR;
- ret = efi_deserialize_load_option(&lo, load_option, &size);
- if (ret != EFI_SUCCESS) {
- log_warning("Invalid load option for %ls\n", varname);
- goto error;
- }
- if (lo.attributes & LOAD_OPTION_ACTIVE) {
- u32 attributes;
- log_debug("%s: trying to load \"%ls\" from %pD\n",
- __func__, lo.label, lo.file_path);
- ret = EFI_CALL(efi_load_image(true, efi_root, lo.file_path,
- NULL, 0, handle));
- if (ret != EFI_SUCCESS) {
- log_warning("Loading %ls '%ls' failed\n",
- varname, lo.label);
- goto error;
- }
- attributes = EFI_VARIABLE_BOOTSERVICE_ACCESS |
- EFI_VARIABLE_RUNTIME_ACCESS;
- size = sizeof(n);
- ret = efi_set_variable_int(L"BootCurrent",
- &efi_global_variable_guid,
- attributes, size, &n, false);
- if (ret != EFI_SUCCESS) {
- if (EFI_CALL(efi_unload_image(*handle))
- != EFI_SUCCESS)
- log_err("Unloading image failed\n");
- goto error;
- }
- log_info("Booting: %ls\n", lo.label);
- } else {
- ret = EFI_LOAD_ERROR;
- }
- error:
- free(load_option);
- return ret;
- }
- /**
- * efi_bootmgr_load() - try to load from BootNext or BootOrder
- *
- * Attempt to load from BootNext or in the order specified by BootOrder
- * EFI variable, the available load-options, finding and returning
- * the first one that can be loaded successfully.
- *
- * @handle: on return handle for the newly installed image
- * Return: status code
- */
- efi_status_t efi_bootmgr_load(efi_handle_t *handle)
- {
- u16 bootnext, *bootorder;
- efi_uintn_t size;
- int i, num;
- efi_status_t ret;
- bs = systab.boottime;
- rs = systab.runtime;
- /* BootNext */
- size = sizeof(bootnext);
- ret = efi_get_variable_int(L"BootNext",
- &efi_global_variable_guid,
- NULL, &size, &bootnext, NULL);
- if (ret == EFI_SUCCESS || ret == EFI_BUFFER_TOO_SMALL) {
- /* BootNext does exist here */
- if (ret == EFI_BUFFER_TOO_SMALL || size != sizeof(u16))
- log_err("BootNext must be 16-bit integer\n");
- /* delete BootNext */
- ret = efi_set_variable_int(L"BootNext",
- &efi_global_variable_guid,
- 0, 0, NULL, false);
- /* load BootNext */
- if (ret == EFI_SUCCESS) {
- if (size == sizeof(u16)) {
- ret = try_load_entry(bootnext, handle);
- if (ret == EFI_SUCCESS)
- return ret;
- log_warning(
- "Loading from BootNext failed, falling back to BootOrder\n");
- }
- } else {
- log_err("Deleting BootNext failed\n");
- }
- }
- /* BootOrder */
- bootorder = get_var(L"BootOrder", &efi_global_variable_guid, &size);
- if (!bootorder) {
- log_info("BootOrder not defined\n");
- ret = EFI_NOT_FOUND;
- goto error;
- }
- num = size / sizeof(uint16_t);
- for (i = 0; i < num; i++) {
- log_debug("%s trying to load Boot%04X\n", __func__,
- bootorder[i]);
- ret = try_load_entry(bootorder[i], handle);
- if (ret == EFI_SUCCESS)
- break;
- }
- free(bootorder);
- error:
- return ret;
- }
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